Summary ObjectiveEarly Hearing Detection and Intervention (EHDI) programs are being established as part of the public health systems in increasing numbers of countries. In developing countries, however, little progress has been made towards implementing NHS programs and South Africa's public and private health care sectors is no exception.The current study presents the first report on a hospital-based UNHS program conducted in the South African private health care sector to provide preliminary results towards advocating for and guiding future programs. MethodsA retrospective study of a UNHS program at a private hospital in urban Gauteng, South Africa over a 4 year period of time was performed. Screening was conducted with Transient Evoked Otoacoustic Emissions (TEOAE) with a rescreen recommended within 6 weeks if referred. Diagnostic audiological assessments were performed on those infants referring the rescreen. The discharge screening costs were subsidized through the hospital birthing package for the first 22 months of the program. openUP (September 2007) ResultsSix thousand two hundred and forty-one newborns were screened from 13,799 hospital births during the first 4 years. Ninety-four percent of these infants were from the well-baby nurseries. During the initial 22 months, whilst the service was subsidized as part of the hospital birthing package, coverage of 75% was attained compared to 20% during the subsequent 26 months. The overall referral rate for the screening program across the 4 years was 11.1% but referral rates decreased by between 2 and 4% for each year of program existence with a 5% rate in year 4. Only 32% of the rescreens were completed at the hospital and no data was available for the remaining infants because parents were provided a choice of follow up centers.Referral for a diagnostic assessment after the rescreens at the hospital was predictive of sensorineural hearing loss in one-third of cases and the estimated prevalence was 3 in every 1000. ConclusionsScreening coverage in the current study was not adequately high and can be attributed to insufficient parental knowledge to make an informed decision. Improvements in program efficiency over time also suggest that pilot programs must be monitored over sufficiently long periods of time to allow observations of optimal efficiency. Initial referral rates and prevalence data indicate a large hearing loss burden and the capacity to implement increasingly efficient programs in South Africa.

The inclusion of the auditory steady-state response (ASSR) into test-batteries for objective audiometry has allowed for clinical comparisons with the most widely used procedure, the auditory brainstem response (ABR). The current study describes ASSR and ABR thresholds for a group of infants and young children with various types and degrees of hearing loss. A sample of 48 subjects (23 female) with a mean age of 2.8+/-1.9 years SD were assessed with a comprehensive test-battery and classified according to type and degree of hearing loss. Thresholds were determined with a broadband click-evoked ABR and single frequency ASSR evoked with continuous tones (0.25-4 kHz) amplitude modulated (67-95 Hz). Mean difference scores (+/-SD) between the ABR and high frequency ASSR thresholds were 9.8 (+/-11), 3.6 (+/-12) and 10.5 (+/-12) dB at 1, 2 and 4 kHz, respectively. An ASSR mean threshold for 2-4 and 1-4 kHz compared to the ABR threshold revealed an average difference of 7 (+/-9) and 7.9 (+/-8) dB, respectively. The overall correlation between the ABR and ASSR thresholds was highest for the mean ASSR thresholds of 2-4 and 1-4 kHz (r=0.92 for both conditions). Correlations between the ABR and individual ASSR frequencies were slightly less (0.82-0.86). The average of the 2-4 kHz ASSR thresholds correlated best with the click-evoked ABR for all categories of hearing loss except for the sensorineural hearing loss category for which the 1-4 kHz ASSR average was better correlated to ABR thresholds. Findings demonstrate the reliability of verifying high frequency ASSR thresholds with a click-evoked ABR as an important cross-check in infants for whom behavioural audiometry may not be possible.

SummaryObjective: The auditory steady-state response (ASSR) to air-conduction (AC) stimuli has been widely incorporated into audiological test-batteries for the pediatric population. The current understanding of ASSR to bone conduction (BC) stimuli, however, is more limited, especially in the case of infants and children. There are few reports on ASSR thresholds to BC stimuli in infants and young children, and none for infants or children with hearing loss. The objective of this study was to investigate BC ASSR thresholds in young children with normal hearing and various types and degrees of hearing loss. Methods: AC and BC ASSR thresholds are reported for 48 young children (mean age AE SD = 2.8 AE 1.9 years; age range = 0.25-11.5 years; 23 female). Hearing status was classified by assessing all children with a comprehensive test battery including tympanometry, diagnostic distortion-product otoacoustic emissions, click-evoked AC auditory brainstem response, AC and BC ASSR thresholds, and an otologic examination. The subjects were assigned to the categories normal hearing, conductive loss, and sensorineural loss (mild-to-moderate or severe-to-profound), for group analysis. AC and BC ASSR stimuli (carrier frequencies: 0.25-4 kHz; 67-95 Hz modulation rates; 100% amplitude and 10% frequency modulated) were presented using the GSI Audera system. Results: : Minimum levels at which spurious BC ASSR occur were established in the group of children with severe-to-profound sensorineural hearing loss (25, 40, 60, 60 and 60 dB for 0.25, 0.5, 1, 2, and 4 kHz, respectively). Children with normal hearing presented mean (1SD) BC ASSR thresholds of 19 (9), 18 (7), 16 (11), 24 (7), and 26 (8) dB HL at 0.25, 0.5, 1, 2, and 4 kHz, respectively. Significantly lower thresholds ( p < 0.0001) were obtained for 0.25, 0.5 and 1 kHz than for 2 and 4 kHz. At

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